The Dairy Farm
The production of milk starts at the dairy farm, where cows produce milk in their udders. They are milked by milking machines, and the milk is transported to facilities for processing. The milk is first pasteurized, and either bottled or used in the production of other products.
There are several breeds of cow that produce milk, but some produce a high volume of milk while others produce milk with a high butterfat content. The chosen breed will depend on what the milk will be used for. South African dairy cow breed include the Holstein, the Jersey, the Ayrshire and the Guernsey.
It is imperative that dairy farmers have a thorough knowledge of breeding, feeding, milk production and milking techniques in order to ensure the production of high-quality milk. The quality and quantity of milk produced by a cow is directly affected by what it eats, so highly nutritional food will improve the quality of the milk. They usually eat silage, oats, bean hay, maize stalks, Lucerne, cottonseed, seedcake or dairymeal.
Cows are no longer milked by hands on dairy farms – we now use milking machines so that time it takes to milk the cow is reduced and so that there is less human contact which ensures the hygiene of the milk product. Before a cow is milked, the teat is tested for mastitis, which is an infection of the udder. If a cow is infected with Mastitis, the milk produced from the cow is not fit for human consumption as it contains harmful bacteria.
Once the teats have been deemed healthy, the cow is connected to the milking machine and milking commences. The milk flows from the udder, through tubes across fine filters that remove impurities and is pumped into stainless steel tanks. The temperature is then lowered to less than 5 degrees Celsius. This temperature needs to be maintained from farm to store (see Cold Chain) and ensures that bacteria production is slowed down (bacteria leads to sour milk).
The unpasteurized milk is taken to the dairy in large, cooled, stainless steel tankers for processing and pasteurization.
The milk is always transported in cooled tankers or trucks to ensure that the cold chain is not broken. (see Cold Chain)
No antibiotics are allowed in the milk, so if any trace of antibiotics is found, the entire batch is rejected. Some people have severe allergic reactions to antibiotics so it is not safe to have this in your milk.
Milk is made up of 88% water and 12% solid particles. This test is done by measuring the freezing point of the milk – if the water content is more than 88% then the freezing point of the milk will change.
This is what gives milk it's creamy taste
Freshness and Keeping Quality:
This is done by using a dye called Resazurin - a dye that changes colour based on the chemical reactions in the milk. The colour indicates the amount of the total number of living bacteria in the milk sample.
Pasteurisation – Pasteurisation is a milk sterilization process by which the temperature of the milk is raised just high enough to destroy harmful bacteria, but without changing the taste (UHT, which means Ultra High Temperature, is different from this). The milk is then pumped through a plate pasteurizer (many stainless steel plates clamped together). Once the process is complete, the milk is chilled to 4 degrees Celsius and kept at this temperature until it is purchased.